1. Field of the Invention
The present invention relates to a tape drive device which, while winding a recording tape that has a free end onto a winding reel, carries out recording of information to the recording tape and/or replaying of information recorded on the recording tape.
2. Description of the Related Art
Recording tapes such as magnetic tapes and the like are used as external recording media for computers and the like. For such recording tapes, recording tape cartridges that accommodate a single reel on which a recording tape is wound, take up little accommodation space when stored and can record large amounts of information, are employed.
When such a recording tape cartridge is used, that is, when information is to be recorded onto the recording tape and/or information recorded on the recording tape is to be replayed, the recording tape cartridge is loaded at a tape drive device. In the tape drive device at which the recording tape cartridge is loaded, a leader member attached at a free end (distal end) of the recording tape is drawn out of the case by drawing-out means (and guiding means).
The leader member is guided to a winding reel of the tape drive device by the drawing-out means, and the recording tape is wound up on this winding reel while being sequentially drawn out from the case. Hence, recording/replaying of information is carried out by a recording head or the like which is provided along a predetermined tape path.
While the recording tape is being wound up on the winding reel of the tape drive device, the leader member attached at the distal end of the recording tape is accommodated inside a reel hub which forms a winding surface of the winding reel.
Specifically, in a structure in which a block-like leader block is used as the leader member, the leader block is inserted into an insetting portion which is formed as a slit provided along a radial direction of the reel hub. In this state, an end surface of the leader block structures a portion of the winding surface of the reel hub. This end surface of the leader block is curvedly formed in an arc shape corresponding to the outer surface of the reel hub, so that the recording tape can be wound smoothly.
However, in a tape drive device provided with this conventional leader member-accommodating structure, the leader block structuring the portion of the winding surface is a structural member of the recording tape cartridge. In other words, this portion of the winding surface is structured by a different leader block for each recording tape cartridge that is loaded. As a result, individual differences, in terms of dimensional accuracy, of the leader blocks are conspicuous at the tape drive device side, and a step that cannot be tolerated may be formed at the winding surface of the reel hub.
Such a step may cause a step (with creasing or deformation) in the recording tape which is wound thereon, and this step is also generated at a portion of the recording tape wound in succeeding layers, which is substantially a recording region (i.e., a “tape impression” may occur). A portion of the recording tape at which such a tape impression (step) has occurred will not maintain a proper separation from the recording head when undergoing recording/replaying of information. Therefore, occurrence of a region at which information cannot be recorded and/or a loss of recorded information may be caused.
In particular, when an opening width of the insetting portion of the reel hub which accommodates the block-like leader block is large (for example, if a width of the recording tape is 12.7 mm, an opening width at an outer peripheral portion of around 12 mm for a reel hub with a diameter of 50 mm), the effect of individual differences between leader block dimensions will be large, and the possibility that the problem described above will occur is high.
Accordingly, a small cylindrical leader pin has been used as a leader member of a recording tape cartridge, in a structure in which a leader block is provided at a tape drive device side such that the leader block which hooks onto the leader pin is accommodated in a reel hub together with the leader pin. This leader block is a structure which is moved by, for example, a cam mechanism, an arm mechanism or the like which is provided with a pin which engages with a through-hole of the leader block. The leader block is moved from a position at which the leader block hooks onto the leader pin, which is accommodated in a case (the recording tape cartridge), to a position at which the leader block is accommodated at the reel hub.
In this structure, the leader block of the tape drive device structures a portion of a winding surface when the leader block is accommodated in an insetting portion of the reel hub. That is, the leader block and the reel hub structure the tape drive device and have a one-to-one correspondence. Therefore, individual differences in dimensional accuracy between recording tape cartridge side components, that is, leader pins, have no effect with regard to steps in the winding surface.
However, this leader block both structures drawing-out means and rotates integrally with the reel hub. Thus, when the leader pin and leader block are accommodated at the reel hub, the engagement of the pin of the cam mechanism or the like with the through-hole should be released such that the cam mechanism or the like does not interfere with rotation of the reel hub. Hence, the leader block becomes movable in the reel hub. That is, the leader block does not have a structure that abuts against the reel hub for being positioned. Moreover, the leader block is moved along a complex path corresponding to the predetermined tape path by a plurality of cam mechanisms, arm mechanisms or the like. Thus, displacement errors of the cam mechanisms, arm mechanisms and the like are aggregated. As a result, the leader block may be not accurately positioned in the reel hub.
Specifically, in this structure, because of the relatively poor positioning accuracy of the tape drive device side leader block relative to the reel hub, a step which causes a tape impression may occur at the winding surface, that is, between an opening periphery portion of the insetting portion of the reel hub and an end surface of the leader block.